“Barking up an unusual tree”: a case of “tree-bark” aortitis with dissection and aortic rupture

Aortitis is an uncommonly seen inflammatory manifestation of disease that can occur in conditions including Takayasu’s arteritis, tuberculosis, tertiary syphilis, and from certain bacterial or fungal pathogens. Aortitis can lead to stenosis, aneurysm, dissection and rupture of the aorta. The pathognomonic “tree-bark aorta” generally refers to the appearance of syphilitic aortitis, a manifestation of untreated tertiary syphilis. In this case study, a male in his 50s impacted his chest on a brick wall in a motor vehicle accident. The patient reported chest pain and malaise, and weeks later had a non-survivable cardiac arrest in hospital. The limited patient history comprised illicit drug use and immigration to Australia from Asia over 20 years previously. At autopsy we found an aneurysmal aortic arch with a thrombotic rupture point and 3 litres of blood in the left pleural cavity, and an extensive type b aortic dissection. The aortic adventitia was grossly thickened, with a bumpy and irregular wrinkling of the intima. On histology, ulcerated intimal calcification, intimal elastic fibre fragmentation, arteritis obliterans and adventitial fibrosis were present. These features are hallmarks of aortitis, most suggestive of syphilitic aortitis, and demonstrate an unusual pathology to consider in cases of aortic aneurysm and aortic dissection.